Markup languages include markup elements that may serve to identify or describe content, including that describe how visible content is to be rendered for display. A markup language document may include markup elements describing a content and/or formatting of content of the document.
Web pages are an example of markup language documents. A web page may be implemented as a set of one or more markup language documents, each of which may include content described using Hypertext Markup Language (HTML) elements or Cascading Style Sheet (CSS) elements, and/or elements of other markup languages. The markup elements of a web page may identify text content, image content, scripting language content, or other forms of content and may, for visible content elements, identify a manner in which the visible content elements are to be rendered. For example, the markup elements may identify a size or placement of visible content elements such as an image, or may describe a formatting of visible content elements such as text. A web browser may, upon download of a web page, review the markup elements of one or more markup language documents and render the visible content elements of the web page on a display based on the markup elements.